If your plan was to install standalone SQL instances on each node and then 'upgrade' them to clustered instances, there is no supported process to make this work.
You can continue to use the instances you installed as standalone SQL instances. If you want to have a clustered SQL instance then you will need to install a new SQL instance to specifically be a SQL clustered instance.
Original author: https://github.com/SQL-FineBuild/Common/wiki/ 1-click install and best practice configuration of SQL Server 2019, 2017 2016, 2014, 2012, 2008 R2, 2008 and 2005.
When I give food to the poor they call me a saint. When I ask why they are poor they call me a communist - Archbishop Hélder Câmara